r31 25t

Somebody correct me if I'm wrong, but I'm sure the bovs are designed like this to combat compressor surge.

I'm keen to give them a go, what sort of current can they handle? I currently run Bosch mec723 coils on a link ecu. I am running twin r33 igniters in parallel this enables me to run the coils up to full dwell. (About 9 amps). Problem I have is the link has only 3 ignition drives, so it is triggering two coils at a time doubling the current (18amps). Do you have any higher rated igniters?

Also check that the fuel tank is able to breath.

Yea mate belts too tight

Are you confident the sensor is scaled correctly in the ecu settings?

I've had a similar problem, my old 30 would do this after a good thrash, there was so much blowby that the fuel was mixing with the oil and making it real thin. Does it make the noise when you rev with no load?

I have the analog outputs from the Kmon fed back into the dyno data acquisition it's awesome, can have knock plotted over anything, boost, afr ect. Can also setup alarms in the dyno software for high levels ect. Am also using STATUS frequency settings. They're mint!

The main reason is the G3's internal map sensor is only limited to around that boost and I'm to tight/lazy to buy another one and wire it in, and to be honest it should be more, the numbers are indicating a problem. Factory r33 rb25de cylinder head and camshafts I=240* E=240* 7.8mm lift Same cams as the rb25det according to the tomei website. I think the head has bumped the CR up a bit - needs to be tested. Thanks mate. The manifold is definitely a twinscroll, not to sure how well it lines up with the turbo flange, will have to check that to. Timing is spot on. I think all going to plan, I'll have it back on the rollers next saturday with a dump pipe only. - It's gunna be loud, but hopefully it makes the numbers.

Power and torque are in kw and nm and I can't remember how I scaled the knock. KW NM AFR KW NM MAP KW NM Knock I'm still working the bugs out on the dyno too which doesn't help much. I put a tilton triple in it the car today and it feels way more savage to drive. Didn't get enough time to put it on the dyno though so not sure if it's transferring more power. Any way don't laugh to hard.

I've seen that video before, and there is a write up on the car here supra t78. The intercooler and exhaust piping sizes are the same as mine according to the posts on the above forum link, but like you say its being run on a dynojet. Also running the wastegate plumbed out is effectively like having a bigger exhaust so that should help a little? I may of found the problem, on a closer review of the dyno sheets I've noticed the there is some slippage when the turbo ramps onto boost, whether it's the tyres or the clutch, I'm not sure. - This is probably where the power is being lost, the engine maybe making an extra 20kw of smoke from the clutch or tyres. I'll have to pay more attention next time it's on the rollers. I'm off to the shed, so will get those sheets posted up today. - no laughing please!! this may be the most inefficient way to make 280kw.

Yea I think so, maybe a 4" exhaust and 22psi. The engine is just a slapper with parts we had lying around. From memory the torque drops off pretty hard after peak @ about 5.5k, like there is a great restriction. I thought with the big turbo the torque should be able to hold a bit longer than it does. It won't take much timing though (probably another sign of a restriction) or maybe the DE head has raised the CR to much. -switch it to E85?

I have a t78-33d 17cm on a rb25det and would like to get an idea of the expected power output. It's currently putting out 280rwkw at 18-19psi on a roller dyno. I thought it would be much more, at least 300-350?? Anyway, specs are as follows. T78 rb25 highflowed injectors stainless highmount exhaust manifold 50mm hks copy wastegate. (not plumbed in) 3" exhaust link g3 ecu stock inlet manifold 2.5" intercooler piping china FMIC stock rb25det block with stock rb25de head stock nissan headgasket oil cooler AFR's on boost are around 11.5 with 10* timing up top. I will get the dyno sheets and post them up soon. Thanks in advance.

I've experienced inconsistent performance when tuning a nistune ecu, (no fault of nistune) turns out I hadn't ticked the "knock copy" box. So basically the ecu had two completely different timing maps available. - Maybe have a look at your main timing and fuel maps and do a quick comparison with the knock maps.

The ecu also requires a start signal (not on your list of things connected). Wack that in, will help a lot with the starting problem.

From memory, for the crank, there are two sets of stamped grading numbers. . . From front on it looks something like this. . . . 112211 <- (Ignore numbers they're just for example, But note there are six of them. These are for the rod journals.) 2211111 <- (again, example numbers, But note there are seven of them. These are for the main journals.) On the block where the sump bolts to, there is also grading numbers. These are for the main tunnel sizes. When selecting graded bearings for the mains or big ends you need to use the "look up tables" in the factory engine manual. If you are using non graded bearings you will normally have the crank and sometimes block machined to suit bearings and/or set desired oil clearance. This is all from memory, so there may be errors. (been a while since I've slapped an engine together).

Is the BOV still plumbed in? After you try the plugs, try putting the BOV back to standard.

Have you still got the factory bov?

Any machining on the crankshaft? Maybe check the journal size, they can vary from factory.

What sort of dyno do you have? The 31 should skid up allright with 300kw!

I've also had this happen. Mine was a faulty injector o-ring (lower one on a side feed injector).

Just a thought, but when VCT is activated is there a dip in oil pressure and supply to the head? Maybe the cylinder head or VCT is not assembled quite right.

You should pressure test the cooling system cold, then warm the engine and do it again. I wonder if not having the fastners in there is alowing the head to move away from the block (when warm) enough to cause the leak?

Not if it's leaking into the oil return side. Have you re-checked head bolt torque?

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I've had marks like these in an engine before and it was due to excessive piston to bore clearance. Do the pistons have polished areas above the top ring on the thrust faces? You get this when the piston "tips" in the bore. Must've been noisy on cold starts..